Efficacy of spinal cord stimulation as an adjunct therapy for chronic refractory angina pectoris.

Introduction: Patients with chronic refractory angina whose symptoms are not controlled with conventional therapies have a poor quality of life. Adjunctive therapies, such as spinal cord stimulation (SCS) may be considered in these cases. We sought to examine whether SCS is associated with changes in exercise capacity and angina severity in these patients.

Methods: We searched Pubmed, Medline and other databases until December 2015. Two reviewers independently extracted data and assessed risk of bias. Exercise capacity included exercise duration and rate pressure product, determined via an exercise test. Angina severity included daily angina frequency and nitrate consumption.

Results: A total of 518 participants (1048.25 person-years of follow-up), from 14 studies met our inclusion criteria. The mean age was 66.8years and 68.5% were men. SCS implant duration ranged from 3weeks to 5years (median: 6months). Using random effects meta-analysis, we found that SCS was associated with a higher exercise duration (1.90min, 95% CI 1.71, 2.06) and lower angina severity, 1.55 less daily angina episodes, (95% CI -1.75, -1.33), 1.54 less daily nitrates consumed, (95% CI -1.81, -1.26), and a 22 points higher SF-36 angina frequency score (95% CI 10.76, 32.81; p<0.0001) on follow-up. The change in rate pressure product was not significant.

Conclusion: This meta-analysis suggests that SCS, as an adjunct therapy to medical management, may be associated with a longer exercise duration and lower angina frequency and nitrate consumption in patients with chronic refractory angina pectoris who are not candidates for percutaneous intervention or revascularization.